Abstract:Model tests on the uplift bearing capacity of jet grouting soil-cement-pile strengthened piles (JPP for short) under four different combinations were carried out based on the self-developed large-scale pile foundation load test equipment system, the model piles were buried by sand pour method. The test results show that:1) different combinations have a great effect on uplift bearing capacity of JPP piles, lower combination carries the highest uplift bearing capacity, its bearing capacity is nearly 1.1 times of three-segment combination, nearly 1.3 times of two-segment combination, nearly 1.4 times of upper combination. 2) the total side resistance of lower combination is the maximum in four combinations under the ultimate uplift capacity. 3) in the process of uplifting test, axial force decreases along the pile depth under each load; the upper lateral resistance reaches firstly the ultimate value and tends to be stable, with the load increasing, the upper lateral resistance takes gradually a full play. (4) the lateral resistance increases gradually and reachs the ultimate value when the relative displacement is small for sand, upper lateral resistance tends to be stable after being ultimate value; lower lateral friction, however, has the increasing trend after reaching the ultimate. In the whole, the relationships between side friction and relative displacement show the hyperbolic model.